Signal-coupling structure



Jan. 26, 1954 H, J, RlBLE-r 2,667,620

SIGNAL-COUPLING STRUCTURE Filed Nov. 4, 1950 HENPVJ. P/BLE T UNITED STATES SIGNAL-COUPLING STRUCTURE Henry J. Riblet, Wellesley Hills, Mass., assignor to Raytheon Manufacturing Company, Newton, Mass., a corporation of Delaware Application November 4, 1950, Serial No. 194,136

7 Claims. (Cl. S33-10) TENT OFFICE l 2 Y This invention relates to signal-coupling strucwill be apparent as the description thereof tures, and more particularly to directional signalprogresses, reference being had to the accomcoupling structures having a Very high direcpanying drawing, wherein: tivity. It is known that, if two signal channels, Fig. 1 illustrates a partially, broken away perfor example, wave guides, are suitably coupled spective view of a wave guide structure embodytogether, for example, by being placed at righting this invention; angles to each other with crossed slots appro- Fig. 2 illustrates a cross-sectional view of the priately positioned in their adjacent walls, energy slot couplings between the first guide and thev which is being propagated in one direction in one second and third guides, respectively; and of the guides will be fed through the slots and Fig. 3 illustrates a cross-sectional View of the be propagated in the other guide in substantially Y slot couplings between the second and third one direction only. guides and the fourth guide, respectively.

This invention discloses a structure whereby Referring now to Figs. 1, 2 and 3. there is shown the directivity of the directional coupling may be a first wave guide I0, which is shown here as increased. Furthermore, it discloses a structure rectangular in form, having wide upper and lower whereby energy propagated in a wave guide may sides II and I2, respectively, and narrow verbe fed toa plurality of different wave guides, and tical sides I3 and I4, respectively. Positioned each may then feed a common or separate load. above guide I0. and at right angles thereto, is a Briefly, the invention comprises a first wave second. guide I 5 having upper and lower wide sides. guide having a second and a third wave guide -0 I B and I1, respectivelyand narrow vertical sides ,Y

positioned. respectively, adjacent opposite walls I 8 and I9, respectively.V The upper side I I of of said rst wave guide, and substantially at right guide I0. and the lower side I1 of guide I5 are angles thereto. The axes of the second and third in contact. and have aV pair of crossed slots 2Q wave guides are displaced by substantially a and 2| cut through both walls II andll. Slot 20 quarter wave length of the signal frequency being is parallel to the axis of guide I0. and slot 2I used along the axis of the first wave guide. is parallel to the axis of guide I5. Said slots in- Energy is directionally coupled from the :Iirst tersect substantially at their mid points. and the wave guide into the second and third wave guides, point of intersection lies substantially on a respectively, by crossed slot couplers. The slots diagonal line of thescuare contacting area beare so positioned that energy is coupled substantween the walls Il and I1.

tally in the same direction in the second and Positioned below wave guide IIl is a third wave thll'd gmdes. l guide 22 having upper and lower wide sides 23 The minor amount of energy which 1S Dl'opaand 2lirespectively, and narrow vertical sides.

gated in the opposite direction in the second and ,W 25 and 25* respectively Theaxis of guide 22 is third guides is coupled into a fourth guide posi- 3 tioned at right angles to said second and third guides, and substantially parallel to said rst guide. The coupling means between the second and third guides and the fourth guide comprise slots positioned parallel to the axis of the fourth 1^. ,al u llls Onhesuoladnhg 35S-'gis rfspl walls thereof. Slots 21 and-28 arepositioned 1n tively which are adjacent the fourth guide and the same manner as the corresponding slots 20 placed by substantially a quarter wave length of the signal frequency used along the axis of wave guide I0. The upper wall 23 of guide 22 vand the lower wall I2 of guide I0 are in contact, and have substantially parallel to the guide I5, and is disa pair of crossed slots-21V and 28 cut through the near the edge of the walls of the fourth guide. and 2' between gulde mand gulde f5' Since the slots in the two guides are substan 45 Wlth ihls Structure 1f a Wave 1s propagated tially a quarter of a wave length apart along the down gulde l fromne end' for example as axis of the fourth guide, and since energy propa- Shown by arrow 29 1t Wm be Coupled through gated in the second and third guides are substan- 510155 20 and 2| and 27 and 23 IIO guides l5 and tial'y ninety degrees out of phase, energy propa- 22, TGSDSCVGIY, and Will be propagated. t0 21 gated from the slots in the second and third large degree, in one direction in guides 22 and guides into the fourth guide will vsubstantially I5, for example, as shown by arrows 3D and 3l,y

add inone direction, and cancel in the other, respectively. These'outputs of guides I5 and 22 thus producing directional coupling in the fourth willcontain substantially equal amounts of power,- guide. and may be used to feed dual loads suchas, for.-

Other and further advantages of the invention 5 example, dual-radiating elements of an antenna,

or the two halves of a balanced modulator or detector.

A small portion of the energy propagated in guides I5 and 22 will travel in the opposite direction in said guides, the proportion of the total energy which this smaller amount comprises being determined by the degree of directivity of the cross-slotted v couplings.

A large portionof this energy is then directively coupled into a fourth Wave guide 32 in the following manner. between wave guides I5 and 22, and has an upper Wide side 33 in contact with the side I1, anda lower wide side 34 in contact with side 23 4of guide 22. Guide 32 also hasnarrow vertical sides i" 35 and 36, respectively. The axis of/'guide 32 is substantially parallel to the axis of .guide if?. and hence substantially perpendicular to the axes of guides I5 and 22. A slot 31 is positioned in the walls I1 and 33, slot 31 being parallel to the axis of cguide32 .and adjacent vertical wall Slot .31 is also positioned substantially `symmetrically on the other sidefof the axis of guide A corresponding Similar slotV 38 is cut iny the wall 34 'of` guide 32v and the wall 23 of guide 22. lSlots 31 and 38 will couple energy fromguides I5 and 22 into guide 32. Y

Since the energy Apropagated in guide 22 lags the energy propagated in guide I5 by substantially ninety degrees when thel input energy to guide Illis in thedirection of arrow 29,.and since slot 38 is substantially ninety electrical degrees displaced from slot 31 along guide 32, energy propagated by slot 38 in theV direction of slotl will substantially vcancel out energy propagated in the samed-irection byfslot 31, while energy propagated in the oppositedirection by slots 3? and38 in guide .32 willadd up, producing substantially complete propagation .in the guide in onedirection, as indicated by arrow 33'. Thus, it may be seen that very 'little energy will propagated in the-opposite direction from Varrow 39,.and hence the overall directivityof this structureY is very highe' The output from guide 32 along arrow 39 may be fed to a third load, such as a wave-san'iplingV structure, and will indicate aproportional amount of the energy `being fed to the loads in vthedirection of arrowsV 30 and `3|. If Adesiredya-n even smaller portion of the energy fed to Vthe loads by arrows y3,!3 and 3| may be indicated by measuring the. output in the opposite direction along guide 32. This structure could also be used vwith a duplexer arrangement in any of the transmit received vsystems where directional coupling is required. Y I Y Thislcompletes the description of the embodimentof the invention illustrated herein. However, many modifications thereof will be apparent to 4persons skilled'in the art without departing from the spirit andscope'of this invention. For example, "other 'coupling structures than vthe crossed'slotscould beused. #and other types of guides other` than rectangular 'wave guides could be used. Indeed, coaxialV cables could be usedgif desired, Therefora'i-tis desired that this invention be not limited tothe particular details of the embodiment described herein, except as defined by the appended claims.

In the claims thatfollow, the term directional coupler shall .be understood to mean `a device consisting of a first, or main, electromagnetic wave transmission line and a second, or auxiliary, electromagnetic Wave transmission line, each line having two'jends, or terminals, the lines being Wave guide 32 is positioned coupled together at a point, or points, intermediate the ends of each, which when there exist waves traveling in both directions in the main line, delivers to one end of the auxiliary line a voltage which is largely a function of the amplitude of the wave going in one preferred direction in the main line, and relatively independent of the wave going in the .opposite-direction in the main line. i f

What is claimed is:

=l. A signal-coupling structure comprising a first signal channel, a second signal channel and va third signal channel, respectively, coupled to said first channel through directional couplers, said second and third channels being, respectively, coupled to a fourth channel, the points Vof coupling of saidsecond and third channels to said fourth channel being substantially a quarter wave length apart along said fourth channel at the frequency of said signal, and the points of coupling `of said second andfthirdichannelsto said first channel being substantially a quarter wavev 'length' apart along said rst channel at said frequency. f

' 2. A signal-coupling structure comprising a first signal channel, 'a second signal channel and a third signal channeL'respectively, coupled to said first channel through Vdirectional couplers, said second and third `channels being, respectively, coupled to a -fourth channel, the points of coupling of said second and third channels to said fourth channel being substantially a quarter wave length apart along said fourth channel at thefrequency of said signal, the wave length distance between-the coupling of said first channel to said second'channel, and the wave length distance between points of said coupling in said second channel being substantially equal to the wave length distance between corresponding points of coupling in said third channel, and the points of coupling of said second and third channels to said first channel being substantially a quarter wave length apart along saidv first channel at said frequency.

3. A signal-coupling structure comprising `a rst wave guide, a second wave guide and a third wave guide, respectively, coupled tov said rst wave guide through directional couplers, said second and third wave guides being, respectivelyy coupled to a fourth wave guide. and the points of couplingof said second and third wave guides to said fourth wave guide being substan tially a quarter wave .length apart alongV said fourth wave guide at the frequency of said signal.

4. A signal-coupling structure comprising a first wave guide, a second wave guide and a third wave guide, respectively, coupled to said first wave guide -through directional couplers, said second and third wave guides being. respectively, coupled to a fourth wave guide, the points of coupling of said second and third Wave guides to said fourth wave guide .being substantially a quarter wave length apart along said fourth wave guide at the frequency Yof. saidwsignal, and the points of coupling of said second and third wave guides to said first wave guide being substantially a quarter wavelength apart along said first wave guide at said frequency.

5. A signal-coupling structure comprising a rst Wave guide, a second wave guide anda third wave guide, respectively, `coupled to said rst wave guide through. directional couplers, vsaid said fourth wave guide being substantially a quarter Wave length apart along said fourth Wave guide at the frequency of said signal, the wave length distance between the coupling of said rst wave guide to said second wave guide, and the wave length distance between points of said coupling in said second Wave guide being sub stantially equal to the Wave length distance between corresponding points of coupling in said third Wave guide, and the points of coupling of said second and third wave guides to said first Wave guide being substantially a quarter wave length apart along said first wave guide at said frequency.

6. A signal-coupling structure comprising a first signal channel, a second signal channel and a third signal channel, respectively, coupled to said flrst channel through directional couplers, said second and third channels being, respective- 1y, coupled to a fourth channel, and the points of coupling of said second and third channels to said fourth channel being substantially a quarter wave length apart along said fourth channel at the frequency of said signal.

7. A signal-coupling structure comprising a first wave guide, a second wave guide and a third Wave guide, respectively, coupled to said iirst wave guide through directional couplers comprising a pair of crossed slots, said second and third wave guides being, respectively, coupled to a fourth wave guide, and the points ci coupling' of said second and third wave guides to said fourth Wave guide being substantially a quarter wave length apart along said fourth wave guide at the frequency of said signal.

HENRY J. RIBLET.

References Cited in the file of this patent UNXTED STATES PATENTS Number Name Date 2,473,274 Bradley June 14, 1949 2,531,447 Lewis Nov. 28, 1950 2,558,385 Purcell June 26, 1951 FOREIGN PATENTS Number Country Date 592,224 Great Britain Sept. 11, 1947 

